Escapement controlled dispensing apparatus



Oct. 18, 1966 F. w. PFLEGER ESCAPEMENT CONTROLLED DISPENSING APPARATUS Filed Dec. 17, 1964 United States Patent 3,279,653 ESCAPEMENT CONTROLLED DISPENSING APPARATUS Frederick W. Pfleger, 1152 Barbara Drive, Cherry Hill Township, Camden County, NJ. Filed Dec. 17, 1964, Ser. No. 418,997 12 Claims. (Cl. 22270) This invention relates to dispensing apparatus and, in particular, to a portable dispensing mechanism that has an extremely low dispensing rate, such as is desired for the injection of certain medicines or chemicals into humans, animals or plants.

Many newly available drugs must be administered at extremely low dosage rates over long periods of time. For example, certain new drugs used in the treatment of human cancer are administered at the rate of 20 cc. over 100 hour period. Conventional dispensers for administering medicines at this rate require motor power and are not portable, with the result that the patent generally must be confined to bed throughout the period of treatment. Moreover, therapy of this type is normally administered in a hospital or clinic, with the result that the treatment is very costly. These results could be avoided by the use of a portable dispensing apparatus.

It has been suggested that a portable dispenser might be battery powered, gas pressure powered, or mechanically powered, and that the medicines or chemicals could be dispensed from plastic containers or special bags. Each of these suggested systems has certain disadvantages. One disadvantage of a system using a battery powered motor is the requirement of replacing or recharging the batteries often due to the energy requirement of the system, resulting in unattended operation for a short period only. A disavantage of 'gas pressured actuators is the requirement of the availability of the gas charges and the high cost of nozzles and regulators. Extremely fine and precision nozzles are required for a low dispensing rate. A disadvantage of the special bag or plastic container is the required availability of special filling equipment and/ or a large inventory of filled bags to handle the various proportions and mixtures that are required.

Accordingly, it is one object of this invention to provide a portable dispensing mechanism which enables the dispensing of material, such as medicines and/or chemicals, at an extremely low rate for a long period of time.

It is another object of this invention to provide a portable dispensing device in which no special power source, tools or replaceable components are required.

It is still another object of this invention to provide a portable dispensing apparatus which is adaptable to the use of a standard medicinal'syringe if the ingredients are variable, or to the use of a disposable, pre-filled syringe for the fixed formula.

It is yet another object of this invention to provide a portable dispensing device in which the dispensing action is of the positive displacement type, so that the rate of administration of the drug is known and fixed.

A further object of this invention is to provide a portable dispensing mechanism which has a very high efficiency so that its size and weight can be kept to a minimum.

In the injection of medicines into the blood system at an extremely low rate, the blood has a tendency to coagulate aroud the orifice of the injecting element. More pressure is then required from the dispenser than would be required in the absence of coagulation. It has been found that this requirement can be avoided by dispensing the medicines in short pulses such that the average rate of flow is maintained.

Accordingly, it is still another object of this invention to provide a portable dispensing apparatus which is operative to dispense material in pulses.

Briefly stated, the invention includes a source of mechanical power operatively coupled to the moveable element of a dispenser, preferably by way of a force multiplier device. The power output of the source is released intermittently under control of a timing mechanism, which may exercise control through an escapement mechanism.

In the accompanying drawing:

FIGURE 1 is a plan view of a portable dispensing apparatus, with cover removed, embodying the invention; and,

FIGURE 2 is a view of the spring motor output spool, drive and control assembly in right side elevation, with the bearing plates being shown in section.

In dispensing systems, one of the first items to be considered is the chamber or container for holding the material to be dispensed. In fluid dispensers in the medical and/ or laboratory field, one of the most perfected and conventional containers is the hypodermic syringe, hereinafter referred to as a syringe. Syringes are readily available in a variety of sizes, are easily sterilized, and are also readily available as disposable units. Professional personnel are very adept at filling syringes and varying the mixtures. Such a syringe is shown in FIGURE 1 mounted in a pair of substantially U shaped spring clips 102 102 each of which is secured to the dispenser housing 103. Only the lower or mechanism portion of the housing is illustrated in the drawing. A cover or upper housing portion 107, only partially shown, of conventional type can be utilized. The syringe 100 has a barrel 101 or chamber and a plunger 106 which fits into the barrel. Barrel 101 is terminated at its lower end in a fitting 104 to which a flexa-ble tubing 105 may be coupled for transporting the dispensed fluid to any desired portion of the body.

In the preferred embodiment illustrated, the movable plunger 106 is the positive displacement element. Alternatively, plunger 106 could be held stationary and the barrel 101 or chamber could be moved to achieve the positive displacement action. When plunger 106 is moved relative to barrel 101, the only energy not used in the actual dispensing operation is the energy required to overcome the friction between plunger 106 and the inner Wall of the barrel 101. In other systems, such as in a roller dispenser or finger action dispenser in which rollers or levers successively compress tubing, energy is required to deform the tubing as well as to overcome friction.

A spring motor, indicated generally by the reference numeral 110, includes a take-up spool 112 and a power output spool 114. Take-up spool 112 is rotatably mounted on a cantilever stud 113 secured to the lower housing 103. A ribbon spring 116, in the form of a long length of spring material, is wound around the two spools 112, 114 and the opposite ends of the spring 116 are secured to the respective spools. The length of the spring 116 required is determined 'by the stroke of the plunger 106 and the ratio of the force required by the plunger relative to the output power of the spring motor 110. This will become clearer as the discussion proceeds. In the preferred arrangement, the spring 116 is a constant force spring of the so-called negator type which will provide uniform force to operate the plunger 106 over its full stroke. However, any other suitable type spring could be used.

Power output spool 114 is mounted on a shaft 120. Also mounted on shaft 120 and constrained to rotate with spool 114 is a pulley drum 122 (FIG. 2). Wrapped around drum 122 and fastened at one end thereto is a length of flexible material illustrated as a cord 124. The output of the spring motor produces a tension force in this cord. Cord 124 is wound around a plurality of pulleys in a multi-pulley system 126 (FIGURE 1) to obtain a desired or necessary step-up of force :for operating the plunger 106. One half of the pulley system 126 comprises a first, stationary set of pulleys 128a mounted on a common shaft 130a carried in bearing supports 132a secured to the dispenser caseor housing 103; The other half of the pulley system comprises a second set of pulleys 1281; mounted on a shaft 130 b which is carried in hearing supports 132b, These latter bearing supports 132b are secured to a moveable carriage 136.

Carriage 166 is provided with a three-point bearing structure 138a, 130b, 138s so that linear motion only can be imparted to the carriage 136 by the pull of the pulley system 126. The bearing points 138a and 13.8b slide on a shaft 140 which is carried by shaft supports 142 and 144 mounted on the case 103. Shaft 140 is parallel to the syringe 100. The other bearing point 1380 slides on a shaft 146 which is carried by a pair of shaft supports 148 and 150 mounted on the case 103. Shaft 146 serves as a guide unit which prevents rotation of the carriage 136 about shaft 140, and maintains the proper alignment between c-arriage 136 and the plunger 106.

A second spring motor 150 is carried on the carriage 136 and comprises a constant force spring 151 wound around a take-up spool 152 and a power output spool 153. Spools 152 and 153 are rotatably mounted on cantilever stunds 154 and 155, respectively, secured to the carriage 136. A cord 156 is attached at one end to the upper shaft support 142 and is wound around a drum 157 mounted on stud 155. Drum 157 and power output spool 153 are constrained to rotate together. When the carriage is pulled in a downward direction by main power cord 124, drum 157 rotates in a clockwise direction to unwind cord 156 the necessary amount. Power output spool 153 is rotated clockwise with drum .157 and winds up the spring 151 in the process. The take-up spool 152 and the force of the spring 151 operate to maintain tension in the cords 156 and 124. Also, the energy stored in the spring 151 as it becomes wound around the power output spool 153 is used to return the carriage to its upper or start position when the system is reset, as will be described.

An 211111158 projects from the carriage 136 at the upper left side thereof, as viewed in FIGURE 1. Secured to this arm 158, on the side thereof facing the plunger 106,

is a pusher bumper 160 and a pair of pull clip fingers 162a and 162b which captivate the free end of the plunger 106. Consequently, any movement of the carriage 136 will, in turn, impart 1:1 movement to the plunger. The pulley system 126 described hereinabove, produces a stepup in force between the output of the main spring motor 10 and the carriage 136 and plunger 106. The step-up in force or power. is a function of the number of pulleys in each of the pulley sets 128a, 128k. The distance travelled in a downward direction by the carriage and plunger per counterclockwise increment of rotation of the main power output spool 1-14varies inversely with the number of pulleys in each set, and thus varies inversely with the force step-up. Accordingly, as mentioned previously, the length of the spring 116 required is a function of the stroke of plunger 106 and the step-up in force produced by the pulley system 126.

In order to provide adequate bearings for the main power output spool 114 and the pulley drum 122, the assembly is sandwiched between thelower housing or case 103 and an upper plate 164, as best seen in FIGURE 2. A major portion of the upper plate 164 is cut away in FIGURE 1 for clarity. of drawing in illustrating the active members as seen in FIGURE 2, an upperbearing 166 and a lower bearing 168 are mounted on the shaft 120, to be further described, and cooperate with hearing holes in the upper plate 164 and case 103, respectively, tov

gives up its energy at a rate equal to the rate at which energy is absorbed by the driven mechanism. In the present system, energy from the main spring motor is released intermittently under the control of an escapement mechanism. The escapement mechanism includes an escapement wheel 170 mounted on shaft and constrained to rotate with power output spool 114 and pulley drum 122 in normal operation. Escapement wheel preferably is a sprocket wheel. An escapement detent or arm 174 is pivotally mounted on a pin 178 and has a pair of fingers 176a, 17Gb spaced to alternately engage teeth 172 of the sprocket wheel 170. The spacing between the engaging surfaces of the fingers 176a, 176b is equal to the sum of the chordal' distance of the wheel 170, at the depth of those two teeth which are adjacent the respective fingers, plus the depth of one tooth, plus nominal clearance. Therefore, it is impossible for the spring motor to free-run, since one finger 176a 1761; or the other will always be in interfering engagement with a tooth on the sprocket wheel :17 0.

Fingers 176a and 17611 are so located that a perpendicular line to the radial surface of the engaged tooth, at the point of engagement, passes through the center of rotation (pin 178) of the escapement arm 174. Consequently, the backor restraining force on the spring motor 110 is in a direction through the center of pivot pin 178, :whereby it does not produce. a couple operative on the escapement arm 174. Therefore, the only power. required to operate the escapement arm 174 is the power to overcome friction at the point of engagement of a finger and sprocket tooth, and friction between the arm 174 and pivot pin 178.

example, is an eight day travel-clock.

on the minute hand shaft 186 of the clock.

The timing cam 182 is a multi-lobe cam. The number of Changing the number of lobes changes the frequency at which lobes determines the pulse rate of the dispenser.

the escapement is operated and thereby provides a method of varying the system pulse rate. Rotation of the earn 182 by the timing mechanism imparts oscillatory motion to the escapement arm 174 through a pair; of cam followers 184a, 184b,'which may be integral parts of the arm 174. The cam followers and cam are designed so that both of the followers 184a, 184b always are in engagement with the cam, resulting in a positive action system. Thus no springs are required to urge, the cam followers against the cam. This is a distince advantage insofar as loading on the timing mechanism is concerned;

if a spring were employed, the timer would have to supply added power to overcome the bias force provided by the spring. As it is, the only energy required of the timing unit is the energy required for its own operation plus the energy to overcome the previously mentioned friction of:

the escapement mechanism. With modern materialsand construction techniques, this friction may be quite. low, with correspondingly small energy required.

Actual dispensing of medicine or other substance from the syringe100 takes place when the plunger 106 is driven in a downward direction. In order to accomplish this, the power out-put spool 114 and the pulley drum 122 must rotate in a counterclockwise direction, under action of the main power spring 116, when the engaged sprocket tooth is released by an engaging finger 17 6a or 17 6b: The

sprocket wheel 170, when released, also must rotate with the power output spool for proper operation.

Qn the other hand, in order to reset the carriage 136 initially to a start position, at the top of its travel for -1 example, the power output spool 114 and pulley drum 122 1 must be rotated in a clockwise direction. However, the sprocket wheel 170 can only be rotated counterclockwise since one of the escapement fingers 176a, 176b, is in engagement with a sprocket tooth and the escapement arm 174 is under control of the cam 182. Attempted rotation of the sprocket wheel 170 in the clockwise direction could cause a jamming action and possible stripping of sprocket teeth 172.

In order to permit clockwise rewind of the power output spool 114 and pulley drum 122 without notation of the sprocket wheel 170, the power assembly of FIGURE 2 is divided into two sections. The upper section comprises the sprocket wheel 170 and upper bearing 166. The lower section comprises pulley drum 122, power output spool 114 and lower bearing 168. The upper and lower sections are held together in alignment by center shaft 120. A knob 190 is located on .the outside of the case 103 and is secured to the lower bearing 168.

Rotational movement of the assembly is controlled by means of a one-way ratchet consisting of a ratchet wheel 194 forming a part of the lower section, and a unidirectional ratchet detent 196 pinned to a member 198 in the upper section (FIGURE 2). Detent 196 is urged by a spring (not shown) into engagement withthe ratchet wheel 194. The teeth of the ratchet wheel 194 and the detent 196 are so arranged that the ratchet wheel maybe rotated freely of the detent in a clockwise direction, as viewed in FIGURE 1, but cannot berotated freely in a counterclockwise direction. Accordingly, in the counterclockwise direction all of the elements 114, 122, 166, 168, 170 and 194 must rotate together. However, the power output spool 114, pulley drum 122, ratchet wheel 194, and bearing 168 may be rotated in the clockwise direction, under control of knob 190, independently of the sprocket wheel 170, upper bearing 166 and detent 196.

In a typical operation of the dispenser, an operator removes the syringe assembly 160 (FIGURE 1) from its holding clips 102a, 102b, 1620, 16212, and either refills the syringe or prepares a replacement. The operator then winds the knob 190 (FIGURE 2) in a direction to rotate power output spool 114 and pulley drum 122 in a clockwise direction (FIGURE 1). This action rewinds the main power spring 116 on the power output spool 114 and causes energy to be stored in the spring. Clockwise rotation of the pulley drum 122 causes the associated cord 124 to unwind, whereupon. the carriage 136 is driven in an upward direction under control of the spring motor 150 mounted on the carriage. In particular, the energy stored in the spring 151 causes the power output spool 153 to rotate in a counterclockwise direction and causes take-up spool 152 to rotate in the clockwise direction. In the process, cord 156 winds around drum 157 to move the carriage in an upward direction and maintain the tension in main cord 124 as the latter is released from drum 122.

The knob 190 is turned by the operator an amount sufficient to allow return of the carriage 136 to a desired starting point. The syringe 100, which now has its plunger 106 withdrawn the correct amount, is placed in the housing with the barrel 101 inserted in the clips 102a and 102b and with the plunger captivated by the clip fingers 162a, 162b.

The clock 180 or timer may be rewound at this time. The dispensing operation thereafter is automatic. Timer 180 rotates shaft 186 continuously to rotate cam 182. Cam 182 oscillates escapement arm 174 back and forth at a rate determined by the speed of shaft 186 and the number of lobes on the cam 182. As an escapement finger 176a or 1761: is rotated out of engagement with a sprocket tooth 172, energy stored in the main spring 116 is released to rotate power output spool 114 counterclockwise a distance equal, or approximately equal, to one-half the angular spacing between adjacent sprocket teeth. In turn, the pulley drum 122 is rotated the same angular amount and winds the cord 124 on the drum. The power output of the spring motor is stepped up by the multipulley system 126 and drives carriage 136 and plunger 106 in a downward direction.

The pulse rate of the dispenser, that is the number of times the plunger 106 is moved in a downward direction per unit of time, is determined by the speed of the timer shaft 186 and the number of lobes on the cam 182. amount of medicine dispensed per pulse is determined by the number and spacing of the teeth 172 on the sprocket wheel 170, the diameter of pulley drum 122, and the number of pulleys. Thus, the pulse rate may be changed by changing the cam 182 to one having a different number of lobes. The amount of medicine dispensed per pulse can be. changed by changing the sprocket wheel 170.

What is claimed is:

1. The combination comprising:

a dispenser having a chamber and a plunger, one of which is moveable;

a spring motor having a rotatable output member;

a timing mechanism controlling the notation of said output member;

a carriage constrained to move parallel to said plunger;

a first set of pulleys mounted in fixed space relation relative to said motor;

a second set of pulleys mounted on said carriage;

a pulley drum constrained to rotate with said output member;

a pulley cord wound around said drum and linking each of said pulleys; and

means on said carriage engaging the moveable member of said dispenser.

2. The combination comprising:

a dispenser having a moveable actuator;

a spring motor including a rotatable take-up spool, a rotatable power output spool, and a length of spring material partially wound around each said spool in a direction to rotate said power output spool in a first angular direction;

a member constrained to rotate in said first angular direction with said power output spool;

a moveable escapement detent engaging said member to prevent rotation thereof;

a rotatable cam controlling the position of said detent;

a timing mechanism for rotating said cam;

a force step-up system coupled to the output'of said spring motor; and

means applying the output of said force step-up system to said actuator.

3. The combination comprising:

a dispenser having a moveable actuator;

a spring motor including an output spool, and a drive spring directly coupled to and urging said spool in a first angular direction;

an escapement member coaxial with said output spool and being constrained to rotate with said output spool in said first angular direction;

a moveable escapement detent engaging said escapement member to prevent rotation thereof in said first angular direction;

a rotatable control member positively positioning said detent;

a timing mechanism for rotating said control memher; and

a force applying member powered by said spring motor and coupled in driving relation with said actuator.

4. The combination comprising:

a moveable output member;

a spring motor including an output spool and a constant force drive spring directly engaging said output spool and urging said spool in a first angular direction;

an escapement member coaxial with said output spool and being constrained to rotate in said first angular direction with said output spool;

a moveable escapement detent selectively engaging said escapement member to prevent rotation thereof in.

said first angular direction;

a rotatable control member positively positioning said detent;

a timing mechanism for rotating said control member;

and

a force applying member powered by said spring member and coupled to said output member.

. The combination comprising:

dispenser having a moveable actuator element; spring mot-or driving said actuator element and including an. output spool, and a'constant force spring directly engaging and urging said output spool to rotate;

a rotatable control wheel coaxial with said output spool and driven thereby, said wheel having spaced projections;

a pivotally mounted escapement arm engaging at least one of said projections; and

NNUI

a timing mechanism for oscillating said escapement arm.

. The combination comprising:

dispenser having a moveable element;

source of constant mechanical force;

force multiplier coupled between said source and said moveable element;

means controlling the release of said force at said source; and

a timing mechanism having an output member operatively coupled t the control means.

7. The combination comprising:

a dispenser having a moveable actuator element;

a spring motor having a rotatable spool, a constant force drive spring directly urging said spool to rotate, and a rotatable control member coaxial with said spool and driven thereby;

means coupling the output of said motor to said actuator element;

a moveable escapement mechanism operatively coupled to said control member;

a cam positively engaging said escapement mechanism;

.and

a timer rotating said cam.

8. The combination comprising:

a dispenser having a moveable element;

a spring motor having a rotatable control member thereon;

a moveable escapement mechanism engaging said control member;

a cam positively engaging said escapement mechanism;

a timing mechanism rotating said cam; and

force step-up means operatively coupled between the output of said spring motor and the moveable element of said dispenser.

9. A control mechanism comprising:

a controlled member;

a spring motor having a spring driven spool, and a rotatable control member coaxial with and driven by said spool;

a moveable escapement mechanism operatively coupled to said control member;

an actuating member positively positioning said escapement mechanism;

a first set of pulleys mounted in fixed spacial relation relative to said motor;

' a second set of pulleys mounted on said carriage;

a pulley drum constrained to rotate with said output member; and

a pulley cord wound around said drum and linking each of said pulleys.

11. Apparatus for the controlled mechanical drive of an output device comprising:

a spring motor including a rotatable take-up spool, a rotatable power output spool, and a length of spring material partially wound around each said spool in a direction to rotate said power output spool in a first angular direction;

a member constrained to rotate in said first angular di-.

rection with-said power output spool;

a moveable escapement detent engaging said mem ber to prevent the rotation thereof in said first angu-.

lar direction during engagement by said detent; V

a rotatable cam controlling the position of said detent;

a timing mechanism for rotating said cam;

a force step-up system coupled to the output of said spring motor; and

means for applying the output of said force step-up system to the output device.

12. Apparatus for the controlled mechanical drive of an output device comprising:

a spring motor including a rotatable take-up spool, a rotatable power output spool, and a length of spring material partially wound around each said spool in a direction to rotate said power output spool in a first angular direction; a member constrained to rotate in said first angular direction with said power output spool;

a moveable escapement detent engaging said memher to prevent the rotation thereof in said firstangn lar direction during engagement by said detent; a rotatable cam controlling the position of saiddetent; a timing mechanism for rotating said cam; and

means coupling the output of said spring motor to the 1 output device.

References Cited by the Examiner UNITED STATES PATENTS 2/1897 Hanks et a1. 185-39 7/1928 Crook et al 18528 X ROBERT B. REEVES, Primary Examiner.

HADD S. LANE, Examiner. 

1. THE COMBINATION COMPRISING: A DISPENSER HAVING A CHAMBER AND A PLUNGER, ONE OF WHICH IS MOVEABLE; A SPRING MOTOR HAVING A ROTATABLE OUTPUT MEMBER; A TIMING MECHANISM CONTROLLING THE ROTATION OF SAID OUTPUT MEMBER; A CARRIAGE CONSTRAINED TO MOVE PARALLEL TO SAID PLUNGER; A FIRST SET OF PULLEYS MOUNTED IN FIXED SPACE RELATION RELATIVE TO SAID MOTOR; A SECOND SET OF PULLEYS MOUNTED ON SAID CARRIAGE; A PULLEY DRUM CONSTRAINED TO ROTATE WITH SAID OUTPUT MEMBER; A PULLEY CORD WOUND AROUND SAID DRUM AND LINKING EACH OF SAID PULLEYS; AND MEANS ON SAID CARRIAGE ENGAGING THE MOVEABLE MEMBER OF SAID DISPENSER. 